1. Field of the Invention
The described technology relates generally to an organic light emitting diode (OLED) display. More particularly, the described technology relates generally to an OLED display that includes two substrates attached together by a sealant.
2. Description of the Related Art
A display device is a device that displays an image, and currently, an organic light emitting diode (OLED) display is in the spotlight.
The OLED display has self luminous characteristics and does not require a separate light source, unlike a liquid crystal display device, and thus can have reduced thickness and weight. Further, the OLED display represents high quality characteristics such as low power consumption, high luminance, and a high reaction speed.
In general, the OLED display includes a first substrate, an OLED that is positioned on the first substrate, a second substrate that is positioned to face the first substrate with the OLED interposed therebetween, and a sealant, such as frit, that is attached to the first and second substrates and seals the space between the first substrate and the second substrate.
In order to bond and seal the first substrate and the second substrate, a sealant is interposed between the first substrate and the second substrate, and a differential pressure is applied between an inner space, which is formed by the first substrate, the sealant and the second substrate, and an outer space, which is formed by the first substrate, the sealant and the outside of the second substrate, in a state in which the first substrate and the second substrate are pressurized while interposing the sealant therebetween. The sealant was cured using a curing means such as a laser, and a display substrate and an encapsulation substrate are attached and sealed with the OLED therebetween.
Even if the sealant is cured, different pressure is formed between the inner space and the outer space of the OLED display, and a central portion of at least one of the first substrate and the second substrate corresponding to the OLED is bent in the other direction due to the differences of the pressure.
However, because a portion of the first substrate or the second substrate that corresponds to the sealant and that contacts the sealant sustains a state that is protruded upward further than the other portion, a portion of the protruded portion is bent. In this way, if a portion of the protruded portion of the first substrate or the second substrate is bent, there is a problem that a Newton's ring phenomenon occurs in the bent portion.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the described technology and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.